Testing system



R. D. CONWAY.

TESTING SYSTEM.

APPLICATION FILED MAY 9. 1918.

1,340,936. Patented May 25, 1920.

Mary/rial Relay //7 ve/vfa/ Royfl. Conway.

UNITED STATES PATENT OFFICE.

ROY D cONwA Y, 0F CHA'IHAM, NEW JERSEY, AS SIGNOR TO WESTERN ELECTRICCOMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

To all whom it may concern:

Be it known that I, ROY D. CONWAY, a citizen of the United Statesresiding at Chatham, in the county of orris, btate of New Jersey, haveinvented certain new and useful Improvements in Testing Systems, ofwhich the following is a full, clear, concise, and exact description.

This invention relates to testing systems and more particularly to suchsystems which are especially applicable to testing marginal relays.

In certain telephone systems, particularly those in which both telegraphand telephone circuits are combined, it is desirable to use forsignaling purposes high frequency currents of approximately 133 cyclespersecond for the purpose of operating signals in connection with thetelephone service, without impairing the telegraph service. The ordinarytype of signal used in connect on with the telephone service beingresponsive only to a current of a very low frequency, such as 16?,-oycles per second, it is necessary to provide means for translating thehigher frequency current into the lower frequency current which issuitable for operating the signal. Marginal relays responsive only tothe currentsof the higher frequency are frequently used' foraccomplishing this translation.

The object of this invention is to provide an improved system fortesting the ad ustment of such marginal type relays.

To attain this object, in accordance with a feature of theinvention,switching means is provided so that the alternating current relay to betested may be operated as a buzzer from a source of direct currentassociated with indicating means serving to indicate the sensitivenessof the adjustment of the contacts of the relay.

The nature of the invention will be more clearly understood from thefollowing specification and the annexed drawing in which the figureshows diagrammatically a relay to he tested and the apparatus fortesting such relay in accordance with the present invention.

' In the accompanying drawing, a marginal relay 6, associated with theconductors 1 and 2 of an ordinary composited line through a retardationcoil 3 and controlling a local circuit through its contact, is connectedthrough normally closed contacts of Specification of Letters Patent.

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a jack 4:. Only that'portion of thecomposited line circuit which isessential to the proper understanding of the invention is shown and itmay be further assumed that conductor 7 connects with the usual localsignaling circuit controlled by the contact of relay 6. A source ofdirect current 23 is adapted to be connected with jack 4 through a plug5 and an indicating device 8. The contacts of jack 4 and plug 5 are sointerconnected that the relay 6 operates as a buzzer when the source ofdirect current is connected to the jack 4. A double wound relay 9 isconnected with jacks 16 and 17 which may be located as desired forconvenience in testing the apparatus. Cooperating with jacks 16 and 17and controlling the relay 9 is an indicating circuit connected with aplug 18. and including lamps 19 and 20. A relay 14: and a slow operatingrelay 13 associated with one contact of the indicating device 8 controlthe indicating lamp 20, while similar relays 11 and 10, respectively,associated with the other contact of the indicating device, controlindicating lamp 19. Condensers 12 and 15 are connected in shunt with thewindings of relays 11 and 14:, respectively, for. the well known purposeof reducing the impedance of the circuits of such relays. In order toreduce the current transmitted through the contacts of the indicatingdevice and the potential impressed upon the needle thereof, resistances21 and 22 are in cluded in the conductors connected-with the needle.

It is thought that-the invention will be more fully comprehended fromthe follow= ing description of the operation of the testing system.\Vhen it is desired to test the contact adjustment of marginal relay 6,the plug 18 is inserted either in jack17 or in jack 16. Assuming thatjack 17 is employed, a circuit is thereupon established from battery 23through theleft-hand winding of relay 9, the contact of relay 10, thetip contacts of jack 17 and plug 18, lamp 19, and the sleeves of plug 18and the jack 17 to ground. Relay 9 operates, completing a circuit frombattery through the contact of relay 9, the winding of relay 10 and thecontact of relay 11, to ground. A second circuit is completed frombattery through the contact of relay 9. the winding of relay 13 and thecontact of relay 141 to ground. A third circuit, also established,extends from Patented May 25, 1920. Application filed May 9, 1918.Serial No. 233,460.

- battery through the contact of relay 9, re-

sistance 21, the needle of indicatin device 8 andresistance 22, toground. Re ay 10 operates, removing the normal shunt circuit existingaround the right-hand winding of relay 9 "and including such winding inseries with the left-hand winding of relay 9 in a circuit establishedfrom battery through the windings of relay 9 in series, the tipcontactsof jack 17 and plug 18, lamp 19 and the sleeve contacts of plug 18 andjack 17, to ground. Due to the high resistance of the two windings ofrelay 9, lamp 19 does not light although relay 9 is maintained in anoperated position. Relay 13 also operates, thereby preventing thelighting of lamp 20. Plug 5 is then inserted in jack 4, opening thenormally closed tip, ring and sleeve contacts thereof to disconnect therelay 6 from its normal association with the retardation coil 3 and thelocal signaling circuit connected with the conductor 7. A circuit isthereupon established from battery through the contact of relay9,indicating device 8, tip contacts of plug 5 and jack 4, both windings ofrelay'G, ring contacts of ack 4 and plug 5,

sleeve contacts of plug 5 andjack 4 and normally closed contact of relay6, to ground. Current flowing over this circuit will cause relay 6 tooperate in the well known manner of a buzzer. Due to the buzzerlikeoperation of relay 6, the current flowing through the indicating device8 is periodically interrupted, thereby causing the needle of such deviceto vibrate in synchronism with such interruptions. If

the adjustment of the contacts of relay 6 is correct or within certainprescribed allowable limits to properly function upon the Ipredetermined operating current, the excur sions of the needle will besuch that although contact may be made with either contact of the devicethe pressure of such contact is such that the associated relays receivean insufiicient amount of current to cause their operation. As a result,lamps 19 and 20 will remain extinguished.

If, however, the contacts of relay 6 are too tightly adjusted, theresistance of. the circuit through the relay is reduced and a greateramount of current flows through the indicating device 8, thereby causingthe.

needle to vibrate to and from the right-hand contact with an amplitudewhich is insufficient to permit the-effective closure of the left-handcontact. Upon the effective closure of the right-hand contact, a circuitis established from battery through the contact of relay 9, resistance21, the needle and the right-hand contact of the indicating device 8 andthe winding of relay 11, to ground. Relay 11 thereupon operates, openingthe circuit of and thereby releasing relay 10. By the closure of itscontact, relay 1O reinstates the normal shunt existing around therighthand high resistance winding of relay 9. The resistance of thecircuit including lamp 19 is thereby sufficiently reduced to permit thelighting of such lamp to indicate that the contacts of rela 6 are tootightly adjusted. When the nee le of the indicating devlce swings awayfrom the right-hand contact, relay 11 is released. Relay 10 is slow tooperate so that although its operating circuit is reestablished by therelease of relayll, it does not become fully operated before theswinging needle of the indicating device returns to the right-handcontact, thereby reoperating relay 11 and consequently causing therelease of relay 10. Therefore -lamp 19 is maintained in a steadilylighted condition.

If the contacts of relay 6 are too loosely adjusted the resistancethereof is increased and less current flows through the winding of therelay and the indicating device so that the needle vibrates to and fromthe left-hand contact with an amplitude which is insuilicient to permitthe effective clothe contact or relay 9, resistance 21, the

needle and the left-hand contact of indicating device 8 and the windingof relay 14, to ground. Relay 14 operates, opening the circuit of, andthereby releasing relay 13. By the closure of its contact, relay 13causes thelighting of lamp 20 over a circuit established from batterythrough the contacts of relay 9 and of. relay 13, the ring contacts ofjack 17 and plug 18, lamp 20 and the sleeve contacts of plug 18 and jack17, to ground. The lighted condition of lamp 20 serves to automaticallyindicate that the contacts of relay 6 are too loosely ail-- justed toproperly function under the service operating conditions. When theneedle of the indicating device swings away from the left-hand contact,relay 14 is released. However, as in the former case, relay-13 is slowto operate and serves to maintain the lamp 20 in a lighted condition,unaffected by the swinging of the needle of the indicating device. a Inactual practice it may be found that convenient arrangement is to locatejack 17 at the jack panel on which jack 4 is located, while jack 16- maybe placed near the marginal relays to be tested. After testing all ofthe marginal relays through jack 17 such relays as may be found to haveincorrect adjustments of their contacts may then be tested through themedium of jack 16. This jack being located near the relay being tested,the contacts of such relay may be adjusted until neither lamp 19 norlamp 20 is lighted.

While the invention has been disclosed as being embodied in the specificarrangement shown on the drawing, it is evident that other forms mayprove desirable under certain conditions.

What is claimed is:

1 In a testing system, in combination with a relay to be tested, asource of direct current, means adapted to serially connect the sourceof current with the winding and the contacts of the relay therebycausing the relay to periodically make and break its own circuit, andmeans to indicate the state of the adjustment of such contacts.

2. In atesting system, in combination with a relay to be tested adaptedto vary its contacts upon a single strength of periodically varyingcurrent having a predetermined frequency, a source of direct current,means adapted to serially connect the source of current with the windingand the contacts ofthe relay thereby causing the relay to periodicallymake and break its own circuit, and means to indicate whether the relaycontacts will function solely under the predetermined serviceconditions.

3. In a testing system, in combination with a relay to be tested, asource of direct current, means adapted to serially connect the sourceof current with the winding and the contacts of the relay therebycausing the relay to make and break its own circuit, and means toindicate variations in the contact pressure. 4.. In a testing system, incombination with a relay to be tested having contacts adapted tofunction under predetermined service conditions when the normal contactpressure is intermediate two limiting values, a source of directcurrent, means adapted to serially connect a source'of current with thewinding and the contacts of the relay thereby causing the relay to makeand break its own circuit and means to automatically indicate when thecontact pressure corresponds with either limiting value.

5. In a testing system, in combination with a relay to be tested adaptedto vary its contacts upon a single strength of a single predeterminedfrequency of periodically varying current, said contacts adjusted to besubject to a pressure intermediate .two limiting values. a source ofdirect current, means adapted to serially connect a source of currentwith the winding and the contacts of the relay to cause the relay tomake and break its own circuit, and means to automatically indicate whenthe contact pressure corresponds with either limiting value.

6. In a testing system, in combination with a relay to be tested, anormal operating circuit for the relay, contacts controlled by the relayand included in a local circuit, an indicating device, a source ofcurrent,

and switching means for disconnecting the relay from its normaloperating circuit and the contacts thereof from the local circuit and toserially include said relay windings and contacts in series with theindicating device and the source of current for determining thesensitiveness of the adjustment of the contacts thereof.

7. In a testing system, in combination with a relay to be tested, asource of current, an indicating device, an indicating signal circuit,switching means for connecting the indicating device with the relay andthe source of current, and additional switching means for connecting theindicating circuittherewith.

8. In a testing system, in combination with a relay to be tested, anindicating de vice, a source of current, an indicating circuit includinga plurality of signaling means, switching means for connectlng theindicating device to the relay, additional switching means forconnecting the indicating circuit with the indicating device, meansunder the control of the last mentioned switching means for completing acircuit through the indicating device and the relay to be tested, andmeans under the control of the indicating device for automaticallyclosing a circuit through one of the signal ing means of the indicatingcircuit.

9. In a system for testing relays, a circuit serially including thecontacts and the windings of the relay to be tested, an indicatingdevice, and means under the control of the indicating device forautomatically indicating the adjustment of'the contacts.

10. In a system for testing relays, a first circuit serially includingthe contacts and windings of the relay to be tested and the winding ofan indicating device, a second circuit normally open includingindicating means, and means under the control of the first mentionedcircuit for closing the second mentioned circuit.

11. In a system for testing relays, a first circuit serially includingthe contacts and the windings of the relay to be tested and the windingof an indicating device, a second circuit including signaling means anda variable resistan'c-e, a third circuit normally open and includingsignaling means, a fourth circuit under the control of the indicatingdevice and including means to vary the resistance of the second circuit,and a fifth circuit under the control of the indicating device andincluding means to close the third circuit.

In witness whereof I hereunto subscribe my name this 3rd day ofv May, A.D. 1918.

' ROY D. CONWAY.

